KEDA Event-Driven Autoscaling

0 messages in queue → 0 pods (scale to zero)
50 messages → 5 pods
500 messages → 50 pods
0 messages again → 0 pods

helm install keda kedacore/keda \
  --namespace keda --create-namespace

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: order-processor
spec:
  scaleTargetRef:
    name: order-processor
  pollingInterval: 15
  cooldownPeriod: 60
  minReplicaCount: 0
  maxReplicaCount: 100
  triggers:
    - type: rabbitmq
      metadata:
        queueName: orders
        queueLength: "10"
        host: amqp://rabbitmq.default.svc:5672

triggers:
  - type: aws-sqs-queue
    metadata:
      queueURL: https://sqs.eu-west-1.amazonaws.com/123456/orders
      queueLength: "5"
      awsRegion: eu-west-1
    authenticationRef:
      name: aws-credentials

triggers:
  - type: kafka
    metadata:
      bootstrapServers: kafka.default.svc:9092
      consumerGroup: order-consumers
      topic: orders
      lagThreshold: "100"

triggers:
  - type: postgresql
    metadata:
      connectionFromEnv: PG_CONNECTION
      query: "SELECT COUNT(*) FROM jobs WHERE status = 'pending'"
      targetQueryValue: "10"

triggers:
  - type: cron
    metadata:
      timezone: Europe/Rome
      start: 0 8 * * 1-5
      end: 0 18 * * 1-5
      desiredReplicas: "5"

triggers:
  - type: prometheus
    metadata:
      serverAddress: http://prometheus.monitoring.svc:9090
      query: sum(rate(http_requests_total{service="api"}[2m]))
      threshold: "100"

spec:
  minReplicaCount: 0    # Scale to zero when idle
  cooldownPeriod: 300   # Wait 5 minutes before scaling to zero

apiVersion: keda.sh/v1alpha1
kind: ScaledJob
metadata:
  name: batch-processor
spec:
  jobTargetRef:
    template:
      spec:
        containers:
          - name: processor
            image: myorg/batch-processor:latest
        restartPolicy: Never
  triggers:
    - type: aws-sqs-queue
      metadata:
        queueURL: https://sqs.eu-west-1.amazonaws.com/123456/batch-jobs
        queueLength: "1"
  maxReplicaCount: 50